JPH0435362A - Picture data coding circuit - Google Patents

Abstract

PURPOSE:To decrease the transmission time through the use of one coding circuit section only and to reduce the cost by using the coding circuit section coding a transmission original in the unit of one line through the changeover for picture data read and data transmission to a line. CONSTITUTION:The coding circuit consists of a coding circuit section 2 coding a transmission original in the unit of one line, a picture memory section 3 storing a coded picture data, a signal changeover section 6 switching the signal transmission of each section and a signal processing section 7 making signal processing of each signal or the like. Then the signal processing section 7 always monitors a coded picture data stored in the picture memory section 3 and a picture data stored in a line buffer memory 9 to control the signal switching section 6 in response to the quantity of the data stored in both the memories and to select the read of the picture data and the data transmission to the line and applies signal processing of each section centralizingly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is directed to improving an image data encoding circuit used in facsimile and the like.

[Prior Art] Recently, facsimile machines have been widely used, and there are facsimile machines with various additional functions. A system has also been developed in which the image data of the next transmission document is stored in the image memory at the same time as the image data of the next transmission document is sent, thereby shortening the transmission time.

Such facsimiles require an image memory with a capacity to store at least one page's worth of image data, but since memory costs are high, the memory capacity is reduced by encoding and compressing the read image data. It is said to be configured to reduce capacity.

By the way, in the image data encoding method, one line of image data read from a transmission document is encoded by one line read immediately before.
The MR encoding method compares image data of a line and encodes the difference, and the M encoding method sequentially encodes only one line of read image data. In the encoding method, once encoding starts, it cannot be interrupted until encoding for one page of the transmitted original is completed.

For example, if the original to be sent is 84 size and the paper size of the destination facsimile is A4, the image data will be automatically reduced and transmitted on the sending side.
Since the encoded image data stored in the image memory cannot be directly reduced, the encoded image data must be decoded to return to the original image data, the decoded image data must be reduced, and then encoded again and sent to the line. It is supposed to be done.

However, in a facsimile machine that has only one encoding circuit, data cannot be sent to the line while image data is being read, and image data of the transmitted document is read while data is being sent to the line. Therefore, the image data reading operation and the data sending operation to the line can only be switched in units of one page of the transmitted document, and since simultaneous parallel processing cannot be performed, the transmission time cannot be shortened. There wasn't.

For this purpose, an encoding circuit section dedicated to reading image data and an encoding circuit section dedicated to transmitting data to the line are provided respectively, so that reading of image data and data transmission to the line are performed simultaneously. Although there are methods to shorten the transmission time, in this type of facsimile, the speed of encoding, decoding, and reduction of image data is very slow compared to the speed of reading the image data of the transmitted original and the speed of transmitting the image data over the line. Although it is fast, a dedicated encoding circuit must be provided for each, which increases cost, so improvements have been desired.

[Tan HE that the invention seeks to solve] In view of the above-mentioned circumstances, the present invention has been proposed by switching the encoding circuit section that encodes the transmission document line by line to reading the image data and sending the data to the line. It is an object of the present invention to provide an image data encoding circuit that can reduce transmission time and cost by using one encoding circuit section.

[Means for solving ffM] The present invention proposed to achieve the above object includes an image data buffer unit that temporarily stores read image data, and a code that encodes the image data line by line. an image memory section that stores encoded image data, an image data reduction section that decodes and reduces the encoded image data based on the encoded image data, and a reduced image data buffer that temporarily stores the reduced image data. The device is configured to include a signal switching section that performs switching of signal transmission of each section, and a signal processing section that performs signal processing of each section.

[Function] In the present invention, when the signal switching unit is switched and connected to the state where it encodes image data under the control of the signal processing unit, the image data read for each line is temporarily stored in the image data buffer. Then, the encoded image data obtained by encoding the stored image data line by line in the encoding circuit section is sequentially stored in the image memory section.

Furthermore, when the signal switching unit is switched to a state where it transmits data to the line under the control of the signal processing unit,
When transmitting the image data as is to the destination without reducing it, the encoded image data stored in the image memory section is sent to the line as is, while when transmitting the reduced image data, the encoded image data stored in the image memory section is sent to the line as is. The stored encoded image data is decoded line by line into the original image data in an image data reduction section, and then reduced. This reduced image data is temporarily stored in a reduced image data buffer section, and then stored. The reduced image data is encoded line by line in the encoding circuit section and sent to the line.

In this way, one encoding circuit section is shared for reading image data and sending data to the line, and the signal processing section monitors the amount of image data stored in the image memory section and the state of data sending to the line. Switching control is performed as appropriate.

[Example] The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the configuration of the main parts of the present invention using a block diagram. an encoding circuit unit that encodes each
4 is an image memory unit that stores encoded image data;
5 is an image data reduction unit that decodes the encoded image data stored in the image memory 1113 into the original image data and then reduces the decoded image data, and 5 temporarily stores fine image data for each line. A reduced image data buffer section 6 is a signal switching section that switches signal transmission between these sections. Further, 8 is an image data reading unit that reads each line of the original to be sent and converts it into image data, and 9 is a line buffer memory that temporarily stores sending data in order to send the data to telephone line l. be. Then, the signal processing section 7 constantly monitors the encoded image data stored in the image memory section 3 and the image data stored in the line buffer memory 9, and changes the signal switching section 6 according to the amount of data stored in both. It controls switching between reading image data and sending data to the line, and centralizes signal processing in each section.

The image data buffer unit 1 is a current line buffer memory l.
a and a previous line buffer memory tb, the image data for one line read by the image data reading section 8 is stored in the current line buffer memory 1a, and when the image data for the next line is read, Current line buffer memory 1a
The image data stored in the previous line buffer memory
After transferring the image data to the current line buffer memory, the read image data is sequentially stored in the current line buffer memory.

The image data reduction unit 4 includes a decoding circuit 4a and an image data reduction circuit 4b, and once encodes the encoded image data for each line transmitted from the image memory unit 3 to the decoding circuit 4.
After that, the decoded image data is decoded into the original image data by the image data reduction circuit 4b.

The reduced image data buffer section 5 has a current line buffer memory 5a and a previous line buffer memory 5b, and when one line of reduced image data is transmitted from the image data reduction section 4, it is stored in the current line buffer memory 5a. , when the next line of reduced image data is transmitted, the reduced image data stored in the current line buffer memory 5a is transferred to the previous line buffer memory 5b, and then the transmitted reduced image data is transferred to the current line buffer memory. The storage operations are performed sequentially.

Further, the signal switching unit 6 has switching contacts a and b, and has switching switches 60a and 60b that operate in conjunction with each other, and a switch 6.
1 to 64, and these changeover switches can be switched under the control of the signal processing section 7. In this embodiment, these changeover switches and switches are constructed using semiconductor elements.

The operation of the image data encoding circuit of the present invention having such a configuration will be explained with reference to the flowcharts of FIGS. 2 and 3. In addition, before sending the image data, in the facsimile, the paper size data of both parties is sent and received by handshake with the destination, and it is determined whether or not it is necessary to reduce the image data, so the image data is not reduced. The explanation will be divided into the case of reduction and the case of reduction.

1. Operation when sending image data as is to the line without reducing it (see Figure 2).

■The changeover switch 60 of the signal switching unit 6 is controlled by the signal processing unit 7.
a and b are connected to the switching contact am, and the switch 62 is closed.

■The image data reading section 8 reads one line of image data of the transmission document and stores it in the current line buffer memory 1a of the image data buffer section 1 (step 100 in FIG. 2).
0.1001).

(2) In this state, since no data to be sent is stored in the line buffer memory 9, encoding of image data is started. In the encoding circuit section 2, the image data stored in the current line buffer memory 1a is transferred to the image data stored in the previous line buffer memory 1b (when reading the first line of each page of the transmission document, the image data is stored in the previous line buffer memory 1b). Since the image data is not stored, the data will be completely white) and the difference will be encoded (MR encoding) (see steps 1002 and 1003 in Figure 2).
).

(2) The encoded image data output from the encoding circuit section 2 is transmitted to the image memory section 3 via the switch 62 and stored therein (see step 1004 in FIG. 2).

■Current line buffer memory 1 of image data buffer section 1
1 line of image data stored in a is transferred to the previous line buffer memory 1b (step 100 in Fig. 2).
(see 6).

The encoded image data is sequentially stored in the image memory unit 3 by repeating the operations ① to ② above. In this way, during the encoding of the image data of the transmission document, the signal processing section 7 determines when the amount of image data accumulated in the image memory section 3 becomes full, and the next operation switches to transmitting the data to the line l. .

(2) Under the control of the signal processing section 7, the switch 62 of the signal switching section 6 is opened and the switch 63 is closed.

■The encoded image data stored in the image memory section 3 is transferred to the line buffer 7 memory 9 via the switch 63, and from the line buffer memory 9 the telephone figure! Encoded image data is sent to Il (see step 1006# in FIG. 2).

In addition, when the amount of image data accumulated in the image memory section 3 decreases while data is being sent to the line l, the signal processing section 7 determines that the signal switching section The switch 63 of No. 6 is opened and the switch 62 is closed, thereby restarting the operation from encoding the image data stored in the image data buffer section 1 (steps 1007 and 100311Wi in FIG. 2).

2. Operation when reducing image data and sending it to the line (
(See Figure 3).

The operation of encoding the read image data (steps 1000 to 1005 in FIG. 3) is the same as the operation shown in steps 1000 to 1°O5 in the flowchart of FIG. omitted.

During encoding of 0 image data, when the amount of image data stored in the image memory unit 3 becomes full, the signal processing unit 7 determines this and switches the signal switching unit 6 to transmit the data to the line l. The switches 60a and 60b are switched to the switching contact side, and the switches 81 and 64 are closed.

■The encoded image data for lines [stored in the image memory unit 3] is transmitted to the image data reduction unit 4 via the switch 64, and the encoded image data is decoded into the original image data in the decoding north circuit'#I4a. The decoded image data is reduced by the image data reduction circuit 4b (step 10 in FIG. 3).
08. 1009 @), and the encoded image data is
Although the number of data bits in one line is different from the number of data bits in one line of original image data, in this embodiment, the end of one line of encoded image data is determined by the number of data bits in one line of the encoded image data, which is the number of data bits in one line of the original image data. It is detected by counting the number of data bits.

■One line of reduced image data reduced by the image data reduction unit 4 is stored in the current line buffer memory 5a of the reduced image data buffer unit δ (step 1010 in FIG. 3).
Participating FI.

■The encoding circuit section 2 converts the reduced image data stored in the current line buffer memory 5a into the reduced image data stored in the previous line buffer memory 5b (the previous line when reading the first line of each page of the transmission document). Buffer memory 1b
Since no reduced image data is stored in , the data is completely white) and the difference is encoded (MR
encoding) (see step 1o11 in Figure 3).

■Transmit the encoded reduced image data to the line buffer memory 9 via the switch 6],
to the telephone line l (see step 1o12 in Fig. 3, Wj).

(2) Transfer the reduced image data stored in the current line buffer memory 6a of the reduced image data buffer section 5 to the previous line buffer memory 5b (see step 1013 in FIG. 3).

■Operations from ■ to ■ above (steps 1008 to 101 in Figure 3)
By repeating step 3), the encoded reduced image data is sequentially sent to line l.

Furthermore, when the amount of image data stored in the image memory unit 3 decreases while data is being sent to line l, the signal processing unit 7 determines this and switches to encoding the image data.
The switches 61 and 64 of the signal switching unit 6 are opened and the switch 62 is closed, and the operation is resumed from encoding the image data stored in the image data buffer unit 1 (
FIG. 3 Step 1014. Step 1003 (N)
.

As described above, in the present invention, the signal processing section 7 constantly monitors the amount of image data stored in the image memory section 3 and the line buffer memory 9, and reads the image data and transfers it to the line according to the amount of stored data. Since the data transmission is switched appropriately using one line as the minimum unit, just by providing one encoding circuit section 2, the data transmission can be performed in the same way as when two dedicated encoding circuits are provided to perform parallel processing. It becomes possible to shorten the time and also to reduce costs.

Note that although the above explanation is based on the MR encoding method, the present invention is not limited to such an encoding method, but can also be applied to an MH encoding method that encodes only current line data. It is also applicable to G3 mode facsimile in which MH and MR encoding are performed alternately.

[Effects of the Invention] According to the present invention, the operations of encoding read image data and transmitting the data to the line can be performed by switching one encoding circuit, so that the transmission time can be shortened and the cost can be reduced. Accordingly, it is possible to provide an image data encoding circuit that reduces the amount of data required.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the main configuration of the present invention, Fig. 2 is a flowchart explaining the operation when transmitting the image data without reducing it, and Fig. 3 shows the operation when the image data is transmitted without reducing it. 12 is a flowchart illustrating the operation when transmitting data. [Description of symbols] 1... Red image data buffer unit 2... Encoding circuit unit 3... Image memory unit 4... Image data reduction unit 6... Reduced image data buffer unit 6... Signal Switching section 7...signal processing section

Claims (1)

[Claims] (1) An image data buffer unit that temporarily stores read image data, an encoding circuit unit that encodes image data line by line, an image memory unit that stores encoded image data, and an encoded image An image data reduction section that decodes and reduces data based on the data, a reduced image data buffer section that temporarily stores the reduced image data, a signal switching section that switches signal transmission between the above sections, and signal processing of each section. An image data encoding circuit comprising: a signal processing section that performs the following steps.